Enhanced Lithium Diffusion of Layered Lithium-Rich oxides with LixMn1.5Ni0.5O4 Nanoscale Surface Coating

Lithium rich oxides have over recent years attracted significant attention as materials able to exhibit high electrical capacity, despite, they exhibit poor rate capability and unstable cycling performance. In this paper, layered lithium rich oxide, Li1.2Mn0.54Ni0.13Co0.13O2 is prepared by solvothermal method and then it is protected by a coating consisting of spinel LixMn1.5Ni0.5O4 giving rise to a series of spinel/layered heterostructured materials. The results conrfim that the presence of spinel coating offers the 3D pathways for the diffusion of lithium ions and assures long-lasting performances of the resulting cathode materials. In particular the heterostructured materials modified with 2 wt% LixMn1.5Ni0.5O4 amount exhibits the highest specific capacity (over 264 mAh g−1 at current density of 40 mA g−1, comparing to 237 mAh g−1 for the pristine layered structured material), excellent initial coulombic efficiency (82%), optimal cycling performance (capacity retention of 94% after 100 cycles at current density of 200 mA g−1) and outstanding rate capability with enhanced lithium diffusion coefficient (7.13 × 10−13 cm−1s−1 of 2 wt% coating amount is much higher than that of 4.23 × 10−13 cm−1s−1 for pristine material electrode). The finding reported in this work provides a novel insight into the design and preparation of high-performance spinel/layered heterostructured materials.

Graphical AbstractThe layered material (Li1.2Mn0.54Ni0.13Co0.13O2) modified with 2 wt% LiMn1.5Ni0.5O4 exhibits the highest specific capacity of 264 mAh g−1 at current density of 40 mA g−1, optimal cycling performance (capacity retention of 94% after 100 cycles at current density of 200 mA g−1) and outstanding rate capability. The presence of spinel coating offers the 3D pathways for the diffusion of lithium ions and assures improved and long-lasting performances of the resulting spinel/layered heterostructured cathode materials.235